Tissue culture of the organ of Corti and the isolated hair cells from the newborn guinea pig

The organ of Corti and isolated hair cells from newborn guinea pig were cultured with the Rose chamber method. The hair cells could be maintained for more than 20 days after explantation when the organ of Corti was cultured as a whole, though the isolated hair cells swelled and degenerated within about 13 hours after explantation. By comparison between the tissue culture of the hair cells with the organ of Corti and isolated hair cell culture, the following conclusions were reached: (1) There are some functional correlations concerning the nutritional requirements and cell metabolism between the hair cells and the supporting cells in addition to the structural correlations. (2) There are no distinct fundamental differences between both inner and outer hair cells about their affectability as a single cell level.

Adenovirus DNA replication. I. Requirement for protein synthesis and isolation of nuclear membrane fractions containing newly synthesized viral DNA and proteins

Nuclear membrane fractions were prepared by two procedures from KB cells pulse labeled with [(3)H]thymidine for 5 min late after infection with adenovirus 2: (i) the M-band technique, which yields a sharp peak containing most of the newly synthesized viral DNA, and (ii) the discontinuous sucrose gradient method, which yields three membrane fractions, one which bands at the interface between sucrose layers at density 1.18 and 1.20 g/ml and contains most of the newly synthesized viral DNA. Studies using cycloheximide to inhibit protein synthesis showed that proteins whose synthesis begins early after infection and occurs in the absence of viral DNA replication are required for viral DNA synthesis late after infection. To study the nature of these proteins, nuclear membrane fractions were isolated from cells labeled with [(3)H]leucine from 6 to 24 h postinfection in the presence of arabinosyl cytosine to block viral DNA replication, and were analyzed by electrophoresis in sodium dodecyl sulfate polyacrylamide gels. Two proteins of molecular weights 75,000 and 45,000 were the major labeled polypeptides in the nuclear membrane fractions prepared from infected cells both by the M-band and the discontinuous sucrose gradient methods. These two proteins were not found in nuclear membrane fractions from uninfected cells. It is suggested that the 75,000 and 45,000 proteins may be early viral gene products that may play a role in the viral DNA replication.

Studies on the diagnosis and pathogenesis of Raynaud's phenomenon of occupational origin

Okada, A., Yamashita, T., Nagano, C., Ikeda, T., Yachi, A., and Shibata, S. (1971).Brit. J. industr. Med.,28, 353-357. Studies on the diagnosis and pathogenesis of Raynaud's phenomenon of occupational origin. Experiments were designed to investigate tests for the diagnosis of Raynaud's phenomenon of occupational origin between attacks and to investigate the pathogenesis, particularly with reference to factors in the patient. The fingertip blood flow was low not only in subjects with Raynaud's phenomenon (positive group) but also in other users of vibrating tools who did not have Raynaud's phenomenon (negative group). This criterion combined with urinary vanillyl mandelic acid and haptoglobin was examined by analysis of discriminant function. The probability of false discrimination was 3%. Histamine iontophoresis performed after noradrenalin iontophoresis with subsequent comparison of pulse wave amplitudes is useful for identification of the positive group. Haptoglobin was significantly increased and the subjects in whom IgM was increased formed a high proportion of the positive group.

Enhancement of Glutamic-Pyruvic Transaminase Activity in Leptospirae by Addition of Rabbit Serum

Glutamic-pyruvic transaminase (GPT) in leptospirae was shown to have an optimal temperature of 30 C and p H 8.0. It was activated by cofactor pyridoxal phosphate, similar to GPT from other sources. However, GPT in all leptospirae, such as Leptospira canicola, L. icterohaemorrhagiae, L. autumnalis , and L. biflexa , evidently had less activity even when pyridoxal phosphate was present, in comparison with the cultivable spirochete Reiter treponeme and Streptococcus faecalis . The low level of activity of leptospiral GPT was enhanced more than 2.5-fold by the addition of about 10% rabbit serum, whereas GPT of S. faecalis did not show such enhancement. Enhancement of leptospiral GPT was greater with rabbit serum than with bovine or horse serum.

Photooxidation by photosystem II of tris-washed chloroplasts

Irradiation of tris-washed chloroplasts with moderate intensities of red light caused a partial bleaching of chloroplast pigments and an inhibition of the hydroquinone-supported photoreduction of NADP. The presence of an electron donor for photosystem 2 (PS2) during the irradiation prevented the bleaching and inhibition. It is concluded that the strong oxidant produced by PS2 accumulates in tris-washed chloroplasts during irradiation and an electron donor for PS2 protects against the photooxidation reactions.

Impingement Cooling of Concave Surfaces With Lines of Circular Air Jets

An experimental study of the heat transfer characteristics between single lines of circular jets and concave cylindrical surfaces is presented. It is intended to model a practically important class of impingement cooling configurations for which existing heat transfer correlations are not obviously applicable. The results clarify the present uncertain position with regard to the optimum spacing between the jet nozzle and the heat transfer surface and with regard to the center-to-center spacing between the jets. Some limited results for a two-dimensional jet impinging on the concave surfaces are also presented.

Inhibition of the Hill Reaction by Tris and Restoration by Electron Donation to Photosystem II

Experiments in which chloroplasts were washed with tris and tricine buffers at different pH's indicated that the non-protonated (uncharged) form of tris was inhibitory to the Hill reaction while the protonated form of tris and the zwitterionic forms of tricine were non-inhibitory. Buffers analogous to tris and tricine gave similar results. Photoreduction of NADP could be restored to the inhibited chloroplasts by adding the reduced forms of p-hydroquinone, p-aminophenol, p-phenylenediamine, benzidine, semicarbazide, and dihydroxydiphenyl, all of which donated electrons to photosystem II. Photoreduction of ferricyanide was shown with those donor systems (benzidine and semicarbazide) which did not react chemically with ferricyanide. Photophosphorylation was also restored with all of the electron donors except semicarbazide.